The recent deadly clashes on the Tunisia-Libya border between security forces and suspected ISIS militants highlight the acute threat the group poses to its neighbour. At least 45 people were reportedly killed in the unrest early on Monday, 7 March, in the city of Ben Gardane. The Tunisian Interior Ministry said at least 28 attackers and 10 soldiers were among the dead. The incident came as a security and military campaign was launched last week to fight 'terrorist groups' that authorities said had infiltrated the country. Following Monday's clashes, Tunisia imposed a curfew to secure the area.

The rise of Islamist militancy remains a pressing challenge for the north African nation. Tunisia fell victim to three major terrorist attacks last year; all of them claimed by ISIS. Two targeted tourists. After an attack in November on a bus carrying the presidential guard in the capital Tunis, Tunisia declared a national state of emergency. This was extended in February, indicating that Tunisia's battle against ISIS is far from over.

Islamist militancy is a great challenge for Tunisia.

Both the June and November attacks in 2015 were carried out by ISIS militants who had trained in neighbouring Libya, a country rife with militant Islamist activity. The chaos that followed the fall of Muammar Gaddafi in 2011 gave violent Islamist groups an opportunity to gain a foothold in the embattled state.

Tunisian authorities have built a 200 kilometre wall along parts of its border with Libya to protect from terrorists next door. The wall, however, does little to address the other threat Tunisia faces: the 5,000 or so Tunisians who have reportedly travelled to fight for ISIS in Iraq and Syria. Tunisians are among the largest contingent of Arab foreign fighters in Iraq and Syria. The very credible threat posed by battle-hardened returnees exacerbates the threat posed by ISIS in Libya. According to an interior ministry spokesman, nearly 700 fighters have returned to Tunisia so far.

The prospect of an Africa-based ISIS affiliate, capable of establishing some kind of territorial 'Islamic State,' has seen hundreds of militants from Nigeria-based ISIS-affiliate Boko Haram travel north across the Sahara to Libya. Foreign fighters have also been arriving from Niger and Chad, while the group has made overtures to militants belonging to Somalia-based al-Shabaab. While Tunisia has borne the brunt of ISIS in Libya, other neighbouring countries, namely Algeria, Sudan, Niger, and Egypt, have also expressed concern over potential spillover and general destabilisation.

The border clashes are part of a trend of destabilisation.

A key aspect of ISIS' operations in Iraq and Syria has been its ability to generate income from oil fields in territories it controls, allowing the group to financially sustain activities without relying on foreign donors. In Libya, ISIS has also been trying to seize control of oil fields as coalition airstrikes continue to target ISIS' financial and logistical capabilities in Syria and Iraq. If the group succeeds in gaining control of these oil fields and is able to set in motion income-generating projects as it has in Iraq and Syria, it will only fuel the group's growth.

While the international community has expressed a desire not to get involved the conflict in Libya, there has been some action. American aircraft have carried out airstrikes against the group, and France, the UK, and Italy have been mulling responses.

The clashes on the Tunisia-Libya border are part of a worrying trend of destabilisation. Unless there is greater cooperation between regional and international powers, ISIS' presence in Libya threatens to grow even more. With an increasing flow of foreign fighters from across the continent and eyes on infrastructure to help finance its activities, the growth of ISIS in Libya may fuel violent extremism beyond Tunisia.